Mercedes-Benz OM656 engine

The OM656 is a turbocharged diesel engine produced by Mercedes-Benz since 2017. It was first introduced in the facelift W222 S-Class.^[1]

Mercedes-Benz OM656
Overview
Manufacturer	Mercedes-Benz
Production	2017–present
Layout
Configuration	Straight-six engine
Displacement	2.9 L (2,927.8 cc), 3.0 L (2,989.8 cc)
Cylinder bore	82 mm (3.23 in)
Piston stroke	92.4 mm (3.64 in)
Cylinder block material	Aluminium alloy
Cylinder head material	Aluminium alloy
Valvetrain	DOHC 4 valves x cyl. with VVT
Compression ratio	15.5:1
Combustion
Supercharger	BorgWarner eBooster electrically driven compressor
Turbocharger	BorgWarner R2S® Biturbo (only one twin-scroll)
Fuel system	Common rail direct injection
Fuel type	Diesel
Cooling system	Water cooled
Output
Power output	210–270 kW (282–362 hp)
Torque output	600–750 N⋅m (443–553 lb⋅ft)
Chronology
Predecessor	Mercedes-Benz OM642 Mercedes-Benz OM629

Design

The OM656 is based on a modular design that is shared with other 4-cylinder and 6-cylinder, petrol and diesel engines.^[2] It is the replacement to the previous V6,^[3] in order to maintain the cost of production between different engines. The OM656 has dual overhead camshafts with variable valve timing, and uses AdBlue injection and exhaust gas recirculation to reduce emissions.^[4] The cylinder walls are coated with arc sprayed steel whose increased porosity aids oil film strength to reduce friction.^[5][6]

Models

Engine	Power	Torque	Years
OM656 D29T R SCR	210 kW (286 PS; 282 hp) at 3,400–4,600 rpm	600 N⋅m (443 lb⋅ft) at 1,200–3,200 rpm	2017–[7]
OM656 D29T SCR	250 kW (340 PS; 335 hp) at 3,600–4,400 rpm	700 N⋅m (516 lb⋅ft) at 1,200–3,200 rpm
OM656 D30T R M	230 kW (313 PS; 308 hp) + 15 kW (20 PS; 20 hp) at 3,400–4,600 rpm	650 N⋅m (479 lb⋅ft) at 1,200–3,200 rpm	05/2023–[8]
OM656 D30T M	270 kW (367 PS; 362 hp) + 15 kW (20 PS; 20 hp) at 3,600–4,200 rpm	750 N⋅m (553 lb⋅ft) at 1,200–3,200 rpm

OM656 D29T R SCR

• 2017–2020 W222 S 350 d^[9]
• 2018–2020 C257 CLS 350 d^[10]
• 2018–2020 W213 E 350 d
• 2018–present W463 G 350 d^[11]
• 2019–present V167 GLE 350 d
• 2020–present X167 GLS 350 d
• 2021–present W223 S 350 d

OM656 D29T SCR

• 2017–2020 W222 S 400 d^[12]
• 2018–2023 C257 CLS 400 d 4MATIC^[10]
• 2018–present W213 E 400 d 4MATIC^[13]
• 2018-present W463 G 400 d
• 2019–present V167 GLE 400 d
• 2020–present X167 GLS 400 d
• 2021–present W223 S 400 d 4MATIC

OM656 D30T R M

• 2023–present W223 S 350 d (RWD-version and 4MATIC-version)^[14]
• 2023–present X167 GLS 350 d 4MATIC^[15]

OM656 D30T M

• 2023–present X254 GLC 450 d 4MATIC^[16]
• 2023–present C254 GLC 450 d Coupe 4MATIC^[17]
• 2023–present W214 E 450 d 4MATIC^[18]
• 2023–present V167 GLE 450 d 4 MATIC^[2]
• 2023–present C167 GLE 450 d Coupe 4MATIC^[3]
• 2023–present W223 S 450 d 4MATIC^[1]
• 2023–present X167 GLS 450 d 4MATIC^[19]
• 2023–present W465 G 450 d